It is a business aviation operator’s responsibility to create schedules that provide sufficient opportunities for rest between duty periods. “This is not trivial—especially when travel over multiple days and across multiple time zones is involved. Air travel also frequently experiences delays due to weather, airport traffic, passenger requirements, and so on. In addition, the nature of human fatigue and alertness is governed by a nonlinear biological process that is complex and highly sensitive to factors such as naps, daylight exposure, and even workload," van Wollen said.

According to the European Business Aviation Association (EBAA), the lack of predictability is one of the contributors to fatigue. “It is also important to observe that our crews fly a lot less than airline pilots. Therefore, for our industry, we do not normally speak of fatigue but rather of tiredness," an EBAA spokesman said.

“Unlike their airline colleagues—given the low number of annual flying hours—cumulative fatigue is rarely a problem for business aviation pilots," he continued. "Due to the unique operational model crews are more prone to fatigue problems associated with a peak activity or a relatively complex or long mission. The periods of more or less intense activity are generally followed by long periods of lull which allow the crews to recover. Regarding the mitigating actions, following an appropriate fatigue risk-management scheme and implementing flight-time limitations (FTL) systems would serve as barriers to fatigue-related occurrences."

Under a fatigue risk-management scheme, the individual crew’s responsibility is to report for work fit for duty. “How can this be accomplished?” asks van Wollen. “By making sleep a priority during time off and being sure to obtain the seven to nine hours of sleep per day recommended by health authorities."

The reality is that many people do not consistently obtain the optimal amount of sleep, for a variety of personal circumstances including caring for a new baby or elderly family member, working a second job, performing home renovations, or other projects, according to van Wollen.

“Even simple things like staying up late watching Netflix can adversely affect sleep,” he said. “Then there are medical conditions, including not only sleep issues (sleep apnea, insomnia) but also body pain, anxiety, and depression that can interfere with sleep. Because there are so many potential pitfalls in assuring enough sleep, organizations invest in technologies such as the psychomotor vigilance test, an objective assay to verify and validate fitness for duty."

Today, in European Union (EU) member states, the prescriptive limits of Annex III to Regulation 3922/91 apply to commercial business aviation to a certain extent. “However, the maximum daily flight duty period in emergency medical services by airplanes (AEMS) and in single-pilot operations is regulated by national rules. Also, Annex III to Regulation 3922/91 does not mandate a fatigue risk-management system (FRMS),” said a spokesperson for EASA.

To update and harmonize the legal requirements and promote fatigue risk management, in 2017 EASA published a notice of proposed amendment (NPA) to the air operations regulations on FTLs for air taxis, AEMS, and helicopter emergency medical services (HEMS). “The NPA used the input from five studies, specifically commissioned by EASA to substantiate its proposals. Three studies specifically deal with hazards and mitigations in those operations and include a scientific study commissioned by EBAA and the European Cockpit Association (ECA)," said EASA.

Based on the NPA and feedback provided by stakeholders, EASA is planning to publish an Opinion of FTL for some business aviation operations (air taxi and AEMS) in the third quarter of 2022. “The Opinion contains requirements for a fully-fledged FRMS (appropriate for large and complex operators), as well as for FRM principles regarding certain duties—e.g., night duties appropriate for small and non-complex operators," said EASA.

According to van Wollen, the best practice is to have an FRMS in place that is integrated with the scheduling system to ingest schedule changes as they are made in real-time, as well as a flight crewmember data collection system to collect subjective and objective information about fatigue levels from flight crews. “These systems need to be complemented by appropriate workflows, policies, and risk controls—all of which should be documented in an FRMS manual," he said.

Currently, FRMS implementation is not very common, although business aviation operators do see the benefits of having such a system in place, according to EBAA. “Business revolves around reputation and EBAA’s members acknowledge that the upfront money and time investment in implementing the FRMS and training their personnel outweigh the potential implications of a safety occurrence caused by fatigue," said EBAA. “The only problem for our industry is that the FRMS is based on historical data. This is a huge issue for our operators that rarely fly the same mission twice.”

The International Standard for Business Aircraft Operations (IS-BAO) was the first standard to mandate—in 2012—a fatigue-management program, which is different from FRMS. “IS-BAO audits validate that the operator has at least the prescriptive elements (performance-based elements optional) and a systemic approach to fatigue-risk reduction,” said a spokesperson for the International Business Aviation Council (IBAC).

Wearable electronics and biomathematical models are slowly becoming more common. “However, it is a long winding road until the operator gets a slightly clearer picture of where its roster/planning will likely create hot spots for fatigue impairments and fatigue calls. At least one large operator managed to greatly reduce the number of those calls and repaid for its FRMS by preventing the usual disruption and costs that follow,” said IBAC. “Considering how intrusive and legally challenging fatigue management can potentially be, building confidence and fine-tuning the system to adjust to human variability can easily take years."